As wireless networks evolve, the demand for high-quality service to a growing number of wireless devices or users increases. Multiple input multiple output (MIMO) is a transmission mode that has been developed to help meet this demand. MIMO is a method for increasing the data throughputs and reliability of a transmission using multiple transmitting and receiving antennas by exploiting multipath propagation. The method includes sending more than one data signal simultaneously using the same resource from multiple antennas of an access node and a wireless device receiving the data signal with multiple antennas. While MIMO increases the data throughputs and reliability of signal transmission to wireless device, it also increases the power consumption of wireless device when sending and receiving data. Power consumption of the wireless device increases since the wireless device needs to receive and decode the signal on multiple paths. Accordingly, wireless device batteries drain faster when communicating via high order MIMO transmissions as compared to low order MIMO transmissions.
Overview
Embodiments described herein include methods and systems for reducing power consumption of a wireless device by controlling a node to reduce a number of transmit paths to the wireless device based on a reported average wireless device transmit power and power headroom. An embodiment of the following description includes a method of controlling an access node. The method includes transmitting data using a plurality of transmit paths, receiving at the access node a transmit power and an available transmit power of a wireless device, monitoring at the access node the received transmit power and the received available transmit power over a period of time, determining at the access node the received transmit power meets a first criteria and the received available transmit power meets a second criteria, and reducing transmit paths from the access node in response to determining the received transmit power meets the first criteria and the received available transmit power meets the second criteria.
Another embodiment of the following description includes a system for transmitting data. The system includes a node and a processor. The processor is configured to transmit data using one or more transmit paths, monitor a received transmit power and a received available transmit power of a wireless device, determine the received transmit power meets a first criteria and the received available transmit power meets a second criteria, and reduce the transmit paths to a lower order in response to determining the received transmit power meets the first criteria and the received available transmit power meets a second criteria.
According to an embodiment, the following description includes a method of controlling a sector of a cell of an access node. The method includes transmitting data within a sector through a plurality of transmit paths, receiving at the access node transmit powers and available transmit powers of wireless devices within the sector. The method further includes determining at the access node an average of the received transmit powers and the received available transmit powers, the average of the received transmit powers meets a first criteria and the average of the received available transmit powers meets a second criteria, and reducing transmit paths from the access node in response to determining the average of the received transmit powers meets the first criteria and the average of received available transmit powers meets the second criteria.